The present invention relates to an image-pickup apparatus such as a digital camera or a video camera, and in particular, to an image-pickup apparatus having a function of displaying a split image serving as a guide image for manual focusing. Focus detection methods in image-pickup apparatuses include a phase difference detection method (pupil division method) that calculates a defocus amount of an image-pickup optical system on the basis of a positional difference amount (a phase difference) between two images formed by light fluxes that passes through two areas different from each other in the image-pickup optical system. Moreover, Japanese Patent Laid-Open No. 2000-156823 discloses an image-pickup apparatus in which image-pickup pixels and focus detection pixels are arranged in a single image-pickup element to perform focus detection by the phase difference detection method without using a sensor dedicated for focus detection.
On the other hand, when a user performs manual focusing, displaying a guide image (focus guide image) for assisting a manual focusing operation enables the user to easily perform the manual focusing.
Japanese Patent Laid-Open No. 59-50671, Japanese Patent Laid-Open No. 2006-154506, and Japanese Patent Laid-Open No. 2001-309210 disclose an image-pickup apparatus that electrically generates and displays on an electrical viewfinder a focus guide image (hereinafter referred to as a split image) corresponding to an optical split image which has been employed for optical viewfinders of film cameras.
The image-pickup apparatus disclosed in Japanese Patent Laid-Open No. 59-50671 photoelectrically converts, by a focus detecting image-pickup element, two object images formed by light fluxes pupil-divided to obtain two electrical images (hereinafter referred to as two pupil-divided images). Then, the image-pickup apparatus synthesizes these pupil-divided images with a normal image (hereinafter referred to as a main image) obtained by an image-pickup element for image capturing to display a split image corresponding to a phase difference of the pupil-divided images in the main image.
The image-pickup apparatus disclosed in Japanese Patent Laid-Open No. 2006-154506 controls a voltage to be applied to a liquid crystal diffractive grating element through which a light flux passes, to display a focus state of an image-pickup optical system of the image-pickup apparatus by the split image.
The image-pickup apparatus disclosed in Japanese Patent Laid-Open No. 2001-309210 calculates a defocus amount of an image-pickup optical system of the image-pickup apparatus and transforms part of a main image into an image like the split image in accordance with the calculation result.
However, the image-pickup apparatus disclosed in Japanese Patent Laid-Open No. 59-50671 generates the split image using the pupil-divided images which have luminance (brightness) information, but have no color information. Therefore, directly displaying the split image in the main image that is a color image displays an unnatural image with no color in only a portion of the split image, which brings an odd feeling to a user. The image-pickup apparatus disclosed in Japanese Patent Laid-Open No. 2000-156823 in which the focus detection pixels arranged in the single image-pickup element output only luminance information has this same point.
The image-pickup apparatus disclosed in Japanese Patent Laid-Open No. 2006-154506 is capable of displaying a color split image. However, this image-pickup apparatus uses the liquid crystal diffractive grating element which is a special element, and that point brings complexity of the configuration and high-cost of the image-pickup apparatus.
Moreover, the image-pickup apparatus disclosed in Japanese Patent Laid-Open No. 2001-309210 as well is capable of displaying a color split image. However, this image-pickup apparatus calculates a defocus amount on the basis of distance-measuring information which is a result of measuring a distance up to an object and lens position information in the image-pickup optical system, to display the split image in accordance with the defocus amount. Therefore, when plural objects exist which have mutually different distances in one split image, it is difficult to display the split image, which makes it difficult to perform manual focusing in the image-pickup apparatus.